1. Field of the Invention
The invention relates to a method and apparatus for introduction into a subterranean well on continuous remedial tubing for activating a ported member, such as a sliding sleeve, positioned on another conduit, such as production tubing. The invention also contemplates a sleeve which is activatable by a remedial continuous tubing-carried device.
2. Description of the Prior Art
In the past, those skilled in the art relating to remedial operations associated with the drilling, production and completion of subterranean oil and gas wells have relied on conventional "snubbing" or hydraulic workover units which utilize threaded or coupled remedial tubing normally inserted through production tubing for use in operations, such as perforating, acidizing and fracturing, corrosion control, pressure testing of tubular goods and vessels, cementing, clean out operations, sand bridge removal, storm valve recovery, insertion of kill strings, wireline tool fishing, and the like.
Continuous coiled remedial tubing and injectors for use therewith have contributed substantially to conventional remedial tubing operations. For example, coil tubing, being continuous, can be inserted into the well faster than threaded and coupled tubing which is furnished in relatively short sections that must be screwed together. In addition, it is easier, when required, to pass continuous tubing through stuffing boxes and blowout preventers because its external diameter is consistently the same size and not interrupted periodically by couplings. The coiled remedial tubing normally is made of steel and is commercially available in sizes from 0.75 inch o.d. through 1.315 inch o.d., but may have a smaller or larger diameter. Typical of such remedial coil tubing and injectors is that generally described in U.S. Pat. No. 3,182,877. The apparatus is commercially referred to as the "Bowen Continuous Spring Tubing Injector Unit" and basically comprises a hydraulically powered injector unit which feeds a continuous remedial tubing string from a coiled or "spooled" workstring contained on a powered and generally portable reel unit into the wellhead by means of two opposed, endless, rotating traction members. Such a reel unit is generally described in U.S. Pat. No. 3,614,019. The upper end of the string which remains on the reel is conventionally connected to the hollow shaft of the reel which permits a liquid or a gas to be pumped through the coiled remedial tubing string by means of a swivel connection. The injector and reel are normally mounted on a single transportable skid, a trailer, or, alternatively, may be componently arranged on skids to facilitate convenient offshore use.
To inject remedial coiled tubing, the injector is arranged on or above the wellhead. The reel unit, containing up to approximately 15,000 feet of continuous coiled metal remedial tubing, is located preferably about 15 to 20 feet from the wellhead. The remedial coiled tubing is brought from the reel in a smooth arc loop through the injector unit and into the well through pressure retention and control equipment.
For many years the desirability of utilizing a subterranean wellbore having a non-vertical or horizontal portion traversing a production formation has been known and appreciated in the prior art. Laterally directed bores are drilled radially, usually horizontally from the primary vertical wellbore, in order to increase contact with the production formation. Most production formations have a substantial horizontal portions and, when conventional vertical wellbores are employed to tap such production formations, a large number of vertical bores must be employed. With the drilling of a wellbore having a non-vertical or horizontal portion traversing the production formation, a much greater area of the production formation may be traversed by the wellbore and the total field of drilling costs may be substantially decreased. Additionally, after a particular horizontal wellbore has produced all of the economically available hydrocarbons, the same vertical wellbore may be re-drilled to establish another horizontal portion extending in another direction and thus prolong the utility of the vertical portion of the well and increase the productivity of the well to include the total production formation.
By use of and reference to the phrase "wellbore" herein, it is intended to include both cased and uncased wells. When uncased wells are completed, the bore hole wall defines the maximum hole diameter at a given location. When cased wells are completed, the "wall" of the well will be the internal diameter of the casing conduit.
By use of the phrase "deviated well" and "deviated wellbore", it is meant to refer to wells and wellbores which comprise a vertical entry section communicating through a relatively short radius curvature portion with a non-vertical or horizontal portion communicating with the production formation. In most instances, the production formation extends for a substantial horizontal extent and the generally liner wellbore portion traverses a substantial horizontal extent of the production formation, at least up to a distance of 1000 to 2000 feet, or more. The radius portion of the wellbore has a curvature of at least 10.degree. per 100 feet of length, and preferably a curvature lying in the range of 10.degree. to 30.degree. per 100 feet of length.
In such deviated wellbores, particularly those having the longer lengths, it is difficult, if not impossible, to activate completion equipment, such as shifting tools for opening and closing sleeves, activating wash tools, and the like, by means of conventional electric or piano wireline means, which are disposed through the production tubing which, in turn, has been implaced within the well section through casing (assuming that the well is encased), or, alternatively, through open hole (if the well is not so encased). As the well section becomes more deviated, the weight suspended from the wireline will become insufficient to actuate the tool, or, at least, to properly position it at the desired location within the deviated portion of the well. Such tools can thus be expected to become improperly lodged or unpositionablle within such well. Accordingly, remedial continuous coiled tubing can be utilized to perform operations in such wells heretofore practiced by application of wireline actuated devices. During acidizing, fracturing, or other completion operations wherein it is desirable to circulate a treating fluid for contact with the production zone, or other areas within the well, it has been known to provide a length of such production tubing with a ported member which has a series of radially extending ports provided within the housing which are selectively closed to prevent fluid flow between the interior and the exterior by means of what is commonly referred to as a "sliding sleeve", which is a member which is implaced within the interior of the device in proximity to the ports, and which is shifted by means of an auxiliary device between open and closed positions. At such time as it is desirable to inject the treating or other fluid into the annulus between the production tubing and the casing (or the open well, in the case of uncased wells), the sleeve is shifted to open the ports for fluid communication between the interior of the production tubing the exterior, or annular area, as defined. Sometimes, such sliding sleeve is manipulated by a device which is carried into the well on wireline, such as electric or piano wire. However, in instances in which such sliding sleeve is positioned within a substantially horizontal section of a subterranean well during the horizontal completion of the well, it will become difficult, if not impossible, to manipulate the sleeve by such means, because the shifting means will either become stuck in the well prior to coming into proximity with the sleeve, or, if properly located, cannot be activated where the shifting device requires application of set down weight to shift the sleeve in a direction to move it to an opening or closing position. The present invention overcomes such deficiencies by providing a device which is carryable into the well upon continuous remedial tubing, described above.